/Engine/Source/Runtime/Engine/Classes/GameFramework/RootMotionSource.h
Examples:
virtual void PrepareRootMotion ( float SimulationTime, float MovementTickTime, const [ACharacter](API\Runtime\Engine\GameFramework\ACharacter) & Character, const [UCharacterMovementComponent](API\Runtime\Engine\GameFramework\UCharacterMovementComponent) & MoveComponent )